Self-assembly of Block Copolymers

In the last few decades, Block copolymers have received considerable attention as a promising platform for the synthesis of nanomaterials and fabrication of nanostructures because of their self-assembling nature to form periodically ordered structures in the nanometer-scale. . Block copolymer consists of two or more chemically distinct polymer blocks which are covalently bound together. These blocks may be thermodynamically incompatible with each other as the entropy of mixing per unit volume is small and varies inversely with molecular weight. The competition between the underlying incompatibility of the constituent polymer blocks and their chemical linkage leads to a self-assembling process with structure sizes in the range of 5-100 nm.  The resulting self-assembled pattern formed is determined by the volume fraction of the components, and length scale of the nanoscopic domain is defined by the molecular weight of the copolymer and the strength of the segmental interaction between the blocks. The typical morphological patterns observed for diblock copolymers in bulk include  spheres, cylinders, bicontinuous structures and lamellae etc. The self-assembled structures formed via block copolymer self-assembly could be further used as templates to generate functional nano-objects. Such templates could be prepared by the so-called selective solvent  approach.